10 year old girl: Do you have any books on freshwater fish?
Me: like a freshwater aquarium?
Me: *smiles* I do! *writes down numbers as I look them up* So are you getting an aquarium then?
Her dad: Yep! 30-50 gallons!
Me: so no pirannah, I hope?"
Her: Oh no!
Her dad: *laughs then tells her about an uncle that had a pirannah*
Me: Good luck with your aquarium! *tells them where the books are*